Bring README.md level with the tree #761

The README's project table is missing 20 projects, it says the project "is currently in setup mode", it never says how to build or test, and its run command omits the --isolated flag every other instruction file uses. A new contributor reads a layout a full module behind. Found in the 2026-09-27 repository review.

Context

• Missing from the project table: src/Modules/Capture/* (3 projects), Backlog.Modules.Sync and .Abstractions, Backlog.Infrastructure.{BlobStorage,Cosmos,Mcp,Sync}, and 11 test projects (Backlog.Modules.Inbox.UnitTests, Backlog.SharedKernel.UnitTests, Backlog.HostComposition.UnitTests, Backlog.Infrastructure.{Capture,Cosmos,Mcp,Sync}.UnitTests, Backlog.Modules.{Capture,Sync,Sync.Api}.UnitTests, Backlog.Aspire.ServiceDefaults.UnitTests).
• Line 10: "The project is currently in setup mode while feature ideas are being shaped and validated."
• Line 94 describes Sync as holding data "only until the desktop picks it up"; Add the Sync bounded context to the domain model #762 covers the domain side of that.
• "Running locally" gives dotnet run --project …; CLAUDE.md, .claude/orch-context.md and .agents/skills/start.md all give aspire start --isolated --non-interactive --apphost …, and the README describes running several worktrees side by side without mentioning --isolated.
• dotnet build / dotnet test appear only in CLAUDE.md, and this repository's dotnet test regularly reports "Zero tests ran"; the README should say to read the assembly count and total.

1. Rewrite "Current state"; add a "Build and test" section; switch the run instructions to the Aspire form with --isolated.
2. Regenerate the project table from the csproj list and add an architecture test that every project under src/ and tests/ appears in it, so it cannot drift again.

Route through delivery:flow-code, config kind, per CLAUDE.md.